Metal-loaded molecular sieves



United States Patent 3,013,986 METAL-LOADED MOLECULAR SIEVES iharles R. Castor, Indianapolis, 11111., assignor to Union Carbide Corporation, a corporation of New York .No Drawing. Filed Sept. 24, 1958, Ser. No. 762,957 12 Claims. (Cl. ,252-455) This invention relates to metal-loaded zeolitic molecular sieves and to a process-for preparing these materials.

The use of metals as catalysts, scavengers, and getters in a number of chemical reactions and chemical systems is well known in the chemical art. Theeiiectivenessof the metal in such cases has been found to depend, to a considerable degree, on the form in which the metal'is .present in the reaction zone.

:It is an object of this invention to provide a process for introducing alkali metals into the internal adsorption area of zeolitic molecular sieves.

It is another object of the invention to provide an alkali metal-loaded zeolitic molecular sieve which is a superior catalyst, scavenger and getter having a higher specific surface of metal for chemesorption and having a corresponding higher surface activity.

Other objects will be apparent from the subsequent disclosure and appended claims.

The process which satisfies the objects of the present invention comprises intimately contacting, in an inert atmosphere, an activated zeolitic molecular sieve with a vapor of an alkali metal whereby at least a substantial quantity of the metal vapor is adsorbed by the molecular sieve, and cooling said metal-containing zeolitic molecular sieve in an inert atmosphere. The product so obtained contains the alkali metal in a form having a high specific surface which is suitable for chemesorption and catalysis, scavenging, and gettering.

Zeolitic molecular sieves, both natural and synthetic, are metal-aluminosilicates. The crystalline structure of these materials is suchthat a relatively largeadsorption area is present inside each'crystal. Access to this area may be had by way of openings, or pores, in the crystal. Molecules are selectively adsorbed by molecular sieves on the basis of their size and polarity, among other things.

Zeolitic molecular sieves consist basically of three-dimensionalframeworks of SiO, and A tetrahedra. The tetrahedra are cross-linked by the sharing of oxygen atoms. The electrovalence of the tetrahedra containing aluminum is balanced by the inclusion in the crystal of a cation, for example metal ions, ammonium ions, amine complexes, or hydrogen ions. The spaces between the tetrahedra may be occupied by water or other adsorbate molecules.

The zeolitesmay be activated vby driving off substantially all of the water of hydration. The space remain- ..ing in the crystals after activation is availablefor adsorption of .adsorbate molecules. Any ,of this space not occupied bygthe adsorbed-alkali metal atoms will be available for adsorption ofmolecules havinga size, shape, v.andienergy which permits .entry of the adsorbate molecules into the pores of themolecular sieves.

vTlhezeolitic molecular sieves to .beuseful in the present invention, must be capable of adsorbing oxygen molecules atthe normal boiling point of oxygen. Included among these are the preferred natural zeolitic molecular sieves, chabazite, faujasite, erionite, mordenite. gmelinite, and ,the calcium form of ,analcite, andthe preferred synthetic zeolitic molecular sieves, zeolite A, D, L, R, S, T, X and .Y. The natural materials are adequately described in the chemical art. The characteristics of the synthetic materials and processes for making them are provided below.

The general formula for zeolite X, expressed in terms of mol fractions of oxides, is as follows:

Patented Dec. 19, 1961 In the formula fM represents aeation, :for example hydrogen or a metal, and ,n its valence. ,The zeolite is activated or made capableof adsorbing certain molecules by the removal of'water'from the crystal as byheata ing. Thus the actual number of mols of water present in the ystal will d penduponthed ree of dehydration or activation of the crystal. Heating .to temperatures .of a ut350 C. has b n oun sufiici n oremqresubstantially all of the adsorbed water.

The cation represented in the formula above ,by'lhe letter M can be changed by conventional ion-exchange techniques. The sodium form of the ,zeolite, designated sodium zeolite X, is the most convenient to manufacture. For this reason the.0ther.forms of .zeolite Xare usually obtained by the modification of sodium zeolite X.

The typical formula for sodium zeolite X is 0.9Na- O:Al O :2.,5Si0 :6.lI-I;,O The major lines in the X-ray difiractiqn pattern of ,z eo'- lite X are ,setjforthin Table A below:

. TABL .A

(1 Value of Reflection in A. l00,5I/I n In obtaining the X-ray diffraction powder patterns, standardtechniques-were employed. The radiation-was the KoC doublet of copper, and a Gieger counter spectrometer with'a strip chart pen recorder was used. -The peak heights, 1, and the positions as a function of -2 0, where 0 is the Bragg angle, were-read from-the spectrometer charge. From these, the-relative intensities,

n where I is the intensity of the strongest line or peak, and

d(obs), the interplanar spacing in A., corresponding to the recorded lines --were calculated. The -X-ray patterns indicate a cubic unit cell of dimensions between 24.5 A.

and 25.5 A.

To makesodium zeolite X, reactants are mixed :in aqueous solution and held at about C. until the crystals of zeolite X are formed. Preferably the reactants should be .such that in the solution thefollowing ratigs prevail: a

SiO /Al O a i a :2 1 H O/Na O 7 3571-1550 Thegeneralformula for'zeolite A, expressed in ttqlils of mol fractionsof oxidesis as follows! ventional ion-exchange techniques. For purposes of convenience the sodium form of zeolite A, designated sodium zeolite A, is synthesized and other forms obtained by the modification of the sodium zeolite A.

When an aqueous colloidal silica sol employed as the major source of silica, zeolite Y may be prepared by preparing an aqueous sodium aluminosilicate mixture having a composition, expressed in terms of oxide-mole- A typical formula for sodium zeolite A is ratios, which falls within one of the following ranges:

0.99Na O: 1.0Al O 1.85SiO :5.1H O

Range 1 Range 2 Range 3 The major lines 1n the X-ray diffraction pattern of zeolite A are set forth in Table B below: Niko/Slog 0.20 m 0.40 0. 41 to 0.61 0.61 to 0. so SiO2/AlzOa 10 to 40 10 to 30 7 to 30 TABLE B IIzO/NazO 25 to so 20 to 60 20 to so Wame MReflemmmA' 100m maintaining the mixture at a temperature of about 100 C. until crystals are formed, and separating the crystals g 23 from the mother liquor. 7.0 ?5 When sodium silicate is employed as the major source gig of silica, zeolite Y may be prepared by preparing an aque- 3.38 ous sodium aluminosilicate mixture having a composi- 35 tion, expressed in terms of oxide-mole-ratios, falling 2.23 12 within one of the following ranges: 2.1.0 22

The same procedures and techniques were employed Rang Rang Range? in obtaining the patterns described in Tables A and B.

To make sodium zeolite A, reactants are mixed in 25 8 i gg 53,353}, aqueous solution and heated at about 100 C. until the Ego/N320: 12 to 90 20 to 00 40 to 90 crystals of zeolite A are formed. Preferably the reactig z i such that m the solunon the followmg maintaining the mixture at a temperature of about 100 prevar C. until crystals are formed, and separating the crystals SiO /Al O 054.3 from the mother liquor. Na O/SiO 1.0-3.0 The composition of zeolite L, expressed in terms of H O/Na O -200 mole ratios of oxides, may be represented as follows:

The chemical formula for zeolite Y expressed in terms l'oio-uigoMZOMAiOjSiOfiFHEO of oxides mole ratios may be written as 35 H 0.9i0.2Na O:Al O :WSiO :XH O wherein M designates a metal, n represents the valence of M; and y" may be any value from 0 to wherein W is a value greater than 3 up to about 5 and about 7 be a Value P to P 40 The more significant d (A.) values, i.e., interplanar Zeohte Y has a characteristic X-ray powder diffraction spacings, f the major lines in the X-ray diff ti Pattern which y be employsd to identify zeolite tern of zeolite L, are given below in Table D.

The X-ray powder diffraction data are shown in Table C.

The values for the interplanar spacing, d, are expressed TABLE 1) in angstrom units. The relative intensity of the lines of r the X-ray powder diffraction data are expressed as VS, 40 :03 3-17-3001 very strong; S, strong; M, medium; W, weak; and VW, 3-07i0-01 i i i TABLE C 4.35:0.04 2.46:0.01

3 14.3-14.4 vs 3'28i0'02 31 i Although there are a number of cations that may be 2-5; 55 present in zeolite L, it is preferred to synthesize the potas- 32 1 79 M sium and potassium-sodium forms of the zeolite, i.e., the :2 3* form in which the exchangeable cations present are sub- 4 1 39 vw stantially all potassium or potassium and sodium ions. 2% 3:33:3-3; g The reactants accordingly employed are readily available 59 322-3124 W 60 and generally water soluble. The exchangeable cations 2; 31851318; present in the zeolite may then conveniently be replaced 3 23; i by other exchangeable cations.

83 271-2173 W The potassium or potassium-sodium forms of zeolite L g? g ggjgzgi it; may be prepared by preparing an aqueous metal alumino- 2 silicate mixture having a composition, expressed in terms 108 384139 M of mole ratios of oxides falling within the following range: 123 2. 22-2. 24 VW r25 5 fig vw K O/ (K O+Na O) From about 0.33 to about 1. 139 1 w (K O+Na O)/SiO From about 0.4 to about 0.5. 1 1%: 353 3; w; SiO /A1 O From about 15 t ab0ut28- 12% 21:1, H O/ (K Oi-Na O) From about 15 to about 41. gag Z2 g maintaining the mixture at a temperature of about 211 1. 70-1. 71 W C. until crystallization occurs, and separating the crystals from the mother liquor.

.The chemical formula for zeoliteD may be written, in terms of oxides, as follows:

wherein x is a value from to 1, w is from about 4.5 to about 4.9, and y, in the fully hydrated form, is about 7. In the preferred form of zeolite d, x is in the range of from 0.4 to 0.6.

'Zeolite D'has anX-ray powder diffraction pattern sub- Zeolite D may be prepared as follows: A sodium-potassium aluminosilicate-water mixture is TABLE F .X-ray difiractionpaztems of zeolileR v [11: inter-planar .spacing ,in .A. 21/1 mam: relative rintensity] Zeo1itejR (I I max.)

Zeolite R may be prepared as follows:

A sodium aluminosilicate-watermixture is prepared such that'the initial composition of the-reactant mixture, in terms of oxide-mole-ratios, falls within any one of the following seven ranges:

I II III IV V VI V11 NEZO/SIOQ 0.20 to 0.40 0.41 to 0.60 0.61 to 0.80 0.81 to 1.0 0.81 to 1.0 1.7 to 1 0 1.2 to 1 4 Sim/111 0 about 4 3.5 to 6.0 3.5 to 6.5 3 to 4.5 about 30 10 to 25 abrut 6 rho N810 22 to 60 30 to 60 to 80 40 to so 50 to 60 00 to 70 80 00 .90

prepared such that the initial composition of the reactant The mixture is maintained at a temperature within the mixture in terms of oxide-mole-ratios is: range of about 100 .C. .to 120 .C. until .crystals ,are fcrmed;.the crystals are then separated from the mother liquor. Nago The chemical formula for zeolite S may be written as: si0 =O-45 to M5 0.9i0.2Na O:AlgO zwsio zXH o wherein W" is from 4.6 to-5. 9 and X, for "the fully Na 0 hydrated form, is from about 6 to 7. i =0.74 to 0.92 Zeolite "S has a characteristic X-ray powder diffraction 2 2 pattern which may be employed to .identifyzeoliteS. The X-ray powder diffraction data are shown in Table .6; ,r, TABLE G =about 28 1 0 X-ray dtfimctzon patterns of synthetzc zeolite S [dzinterplanar spacing 111A. ,I/ I..max..:re.1ati\ze intensity] H2O i 7 0,11. 100 Na2O.+ K 0 18 to 45 (I/Imax.)

11.88 77 112 .a The mixture is maintained at a temperature within the 51 96 0 range of about 100 C. to 120 C. until crystals .are 2123 2% formed; the crystals are then separated from the mother 3-3 79 liquor. ,3: 41 The chemical formula for zeolite R may be written as: 2,: 21073 50 09:02 Na O:Al O :WSiO :XH O 3; 33? i; as: wherein w 'is' from 3.45 to 3.65, andfX, for the fully 2 .1}, hydrated form, is about 7. 353 1% Zeolite-R has an'X-ray powder diffraction pattern sub- 1. 722 y 732 stantially like that shown in'Table F.

falls within the following range when the source of silica is an aqueous colloidal silica sol:

Na O/SiO 0.3 to 0.6 SiO /Al O 6 to 10 H O/Na O 20 to 100 and falls within the following range when the source of silica is sodium silicate:

Na O /SiO About 0.5 About H O/Na O About 18 wherein x may be any value from about 0.1 to about 0.8, and y" may be any value from about to about 8. Zeolite T may be identified and distinguished from other zeolites, and other crystalline substances, by its X-ray powder diffraction pattern. The data which are set forth below in Table H are for a typical example of zeolite T.

TABLE H Interplanar Relative Bragg Angle, 20 Spacing, Intensity,

d (A.) 100 I/I Zeolite T may be prepared by preparing an aqueous sodium-potassium aluminosilicate mixture having a composition, expressed in terms of mole ratios of oxides, falling within the following range:

Na O/(Na O+K O) From about 0.7 to about 0.8. (Na O-l-K OWSiO From about 0.4 to about 0.5. 'SiO /Al O About 20 to 28. H O/(Na O-l-K O) About 40 to 42.

maintaining the mixture at a temperature of about C. until crystallization occurs, and separating the crystals from the mother liquor.

To prepare the elemental metalcontaining zeolitic molecular sieves by the process of the present invention, it is first necessary to activate the zeolitic molecular sieves, i.e., to drive olf substantially all of the contained water. This may be accomplished by heating the zeolitic molecular sieves up to a temperature of about 350 C. in a flowing stream of inert dry gas or in a vacuum. The activated molecular sieve is then ready to receive the alkali metal vapors.

The activated zeolitic molecular sieves and the alkali metal vapors may be brought into contact with each other by mixing molten metal and the molecular sieves, by vaporizing the metal in the presence of the molecular sieves, or by entraining the metal vapors in an inert gas and passing the metal vapor-containing gas stream through a bed of the molecular sieves.

In an example of the invention, 29 grams of activated sodium zeolite X were heated to C. Four grams of metallic sodium were added with stirring in a nitrogen atmosphere. The sodium (melting point 97.5 C.) melted and dispersed evenly throughout the sodium zeolite X, yielding a product with a jet black color. X- ray diffraction showed no destruction of the sodium zeolite X crystal structure.

In another example of the invention, 100 grams of activated sodium zeolite X were charged to a flask and heated to 200 C. Lithium metal in ribbon form was added in small portions of about .3 to about .4 gram with continuous stirring of the mixture until about 3 grams of lithium had been added in a period of about 2 /2 hours. The stirring was continued for an additional hour. The X-ray diffraction data for the gray colored product indicated that the crystal structure of sodium zeolite X was retained. The product was added to water and a gas, apparently hydrogen, was evolved.

Many advantages accrue from the use of alkali metalloaded zeolitic molecular sieves that are not available with other materials. For example, it is well known that the alkali metals are good catalysts for the polymerization of olefins. However, by employing alkali metal-loaded zeolitic molecular sieves as catalysts it is possible to selectively polymerize specific olefins from a mixture of olefins, e.g., short straight-chain olefins may be selectively polymerized from admixture with more complex branchchained olefins, without the necessity for first isolating the components of the mixture.

Similarly, alkali metals have been recognized as good getters for oxygen and other gases. However, the alkali metal-loaded zeolitic molecular sieves may be employed for selective gettering, Without contamination of the system being so treated.

Still another advantage of employing the product of the present invention resides in the manner in which the metal is held in the molecular sieve. Catalysts consisting of alkali metals on a catalyst support usually have the problem that the metal tends to migrate in the catalyst bed with a corresponding tendency for the metal to collect in some areas of the bed leaving other areas metal deficient. This tends to decrease the active metal surface available for catalysis and to give non-uniformity of catalysis through the bed. By incorporating the metals on the inside of the zeolitic molecular sieves, the tendency for the metal to migrate is minimized with a corresponding increase in the efficiency of catalysis.

. By incorp'orating'the alkali metals in the-ze'o'litic molecular sieves in accordance with the present invention, a suitable means for adding these metals to other chemical systems is provided. By adding the alkali metals in this form, it is possible to control the reactivity of the metals to a much greater extent than is possible by direct addition of the metals to the same chemical systems.

Still another use and advantage found for alkali metalloaded zeolitic molecular sieves is found in'the preparation of zeolitic molecular sieves loaded withthe reactive refractory metals of groups IV, V, and VI of the periodic table. A halide of one of these reactive refractory metals may be intimately mixed with an alkali metal-loaded zeolitic molecular sieve, whereupon some of the halide will be adsorbed. The adsorbed halide reacts with the alkali metal present inside the molecular sievetodeposit the reactive refractory metal also inside the molecular sieve. This may be illustratedby the following example.

Fifty grams of activated sodium zeolite X were placed in a flask and heatedto 125 C. in argon. Then 6 grams of lump sodium were added with-stirring and after dispersion in'the zeolite, 12.4 grams of titanium tetrachloride was added slowly'with continuedstirring. After reaction was complete'the material contained 62 percent titanium metal.

To further illustrate the utility of the materials of the present invention zeolite X containing sodium amalgam was employed to remove diborane from diborane-contaminated silane.

In preparing the adsorbent'bed, about 17 grams of sodium zeolite X were placed in a glass tube to form a zeolite column 9 cm. long and 20 min. in diameter. About 0.26 gram of sodium were placed-in atube connecting to the zeolite column. The zeolite thus prepared was surrounded by a furnace and heated for about 16 hours at 370-400" C. under vacuurntoremove adsorbed water.

The furnace was then lowered to surround both the zeolite and the sodium containing tube. The temperature of the system eventually stabilized at about 500 G in the sodium zone and slightly higher in the zeolite zone, during this additional heating period of about 16 hour the furnace was kept at about 45O-500 C.

About 1.3 grams of mercury were next placed in the bottom of the zeolite column and heated at 100-l50 C.

under vacuum. The mercury vapor thus emitted entered I the zeolite bed to form asodium amalgam within the porous structure thereof.

In'preparing the gaseous mixture to be purified, silane and diborane were added to a container so that the partial pressure of silane was about 158 mm. of mercury,'and that of the diborane about 64 mm. of mercury. .This gaseous mixture was passed through the above prepared sodium amalgam-containing zeolite bed.

The flow of gas having passed through the zeolite bed was then collected, measured, and-found to have a vapor pressure of 152 mm. of mercury which'was substantially that of the silane starting pressure thereby indicating the dibo'rane was quantitatively removed.

As used herein the term activation is employed to designate the removal of water from-the zeolitic molecular sieves, i.e., dehydration, and does not refer to catalytic activity. The zeolitic molecular sieves containing the elemental metal exhibit catalytic activity.

The products of the present invention have a surface area about four times that expected with most alumina, silica or aluminosilicate supported metals thereby providing a greater surface area available for reaction. Since the external surface of the molecular sieve represents less than 1 percent of the total surface area it may be seen that there is an extremely large area available for chemisorption and catalysis in the internal portion of the molecular sieve. Since this region is available only through pores of molecular size it may be seen that selective chemisorption and catalysis may be obtained in a system containing the pores.

.Zeolite A is described and claimed-in U.S.'-Patent No.

2,882,243, issued April 14, 1959, to R. ,M. Milton.

Zeolite D is'clescribed and claimed in US. patent-rapplication Serial No. 680,383, filed August 26, 1957.

Zeolite L is described and claimed in U.S.-pateut applicationSerial No. 711,565, filed January 28, 11958.

Zeolite R is described and :clair'nedin US. patent application Serial No. 630,381, filed August 26, 1957.

Zeolite S is described and claimed inU.S. patentapplication Serial No. 724,843, filed March 31, 1958.

Zeolite T is describedand claimed in U.-S. patent application Serial No. 733,819, filed May 8, 1958, now U.-S. Patent No. 2,950,952.

Zeolite X is described and claimed in U.S. Patent .No. 2,882,244, issued April 14, 1959 to R. M. Milton.

Zeolite Y is described and claimed in U.S.. patent application Serial No. 728,057, filed April 14, 1958.

The metal-containing synthetic .zeolites A, X, and Y, and natural zeolite faujasite have been found .to be most satisfactory and .useful for the'purposes of the present invention.

Erionite is a naturally occurring zeolite, described originally by Eakle, Am. J. Science (4'),06, 66 (.1898). :It is most readily identified by its characteristic X-ray powder diffraction pattern. The dspacing .in A, and relative intensities thereof, obtained on'a well-crystallized-' specimen are tabulated below.

X-ray powder data, 'erionite .d-spaclng, Relative A. Intensity, v I/IoXlOO 11.38 100 0.06 V 10 7. 50 10 '6. 56 40 6.24 10 5. 68 10 5. 34 10 4. 56 10 4. 31 40 t t. 15 v20 3. 20 *3. 74 40 3. 58 I 30 3. 30 10 3. 27 10 3.20 10 3.16 10 314. -10 :3. 00 5 2.92 5 "2.86 30 2. 83 30 2. 805 20 2.07 10 2. 59 5 2. 40 g 10 2.47 v 10 2.20 5 2.1.1 5 1.83 6 1. 83 ,5 l. 77 10 1.65 10 What is claimed is: V

1. As a new composition of matter a dehydrated rigid, three-dimensional, crystalline metal aluminosilicate zeolite of the molecular sieve type capable of adsorbing oxygen internally at the normal boiling point of oxygen containing at least one elemental alkali metal in the inner adsorption region.

2. A composition of matter in accordance with claim 1 whereinsaid alkali metal is sodium.

3. A composition of matter in accordance with claim 1 wherein said alkali metal is lithium.

4. A process for preparing an elemental alkali metalloaded rigid, three-dimensional, crystalline metal aluminosilicate zeolite of the molecular sieve type which comprises dehydrating a rigid, three-dimensional, crystalline 11 metal aluminosilicate zeolite of the molecular sieve type capable of adsorbing oxygen internally at the normal boiling point of oxygen whereby substantially all of the water of hydration of said crystalline metal aluminosilicate zeolite of the molecular sieve type is removed; intimately contacting in an inert atmosphere said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type with the vapor of at least one elemental alkali metal, the temperature of said vapor being below the temperature of crystal destruction for said crystalline metal aluminosilicate zeolite of the molecular sieve type, whereby said metal vapor is adsorbed by said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type; and cooling said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type containing said adsorbed metal vapor in an inert atmosphere whereby said adsorbed elemental metal is retained in the inner adsorption region of said crystalline metal aluminosilicate zeolite of the molecular sieve type.

5. A process for preparing an elemental sodium-com taining rigid, three-dimensional, crystalline metal aluminosilicate zeolite of the molecular sieve type which comprises dehydrating a rigid, three-dimensional, crystalline metal aluminosilicate zeolite of the molecular sieve type capable of adsorbing oxygen internally at the normal boiling point of oxygen whereby substantially all of the water of hydration of said crystalline metal aluminosilicate zeolite of the molecular sieve type is removed; intimately contacting in an inert atmosphere said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type with molten sodium metal at a temperature below the temperature of destruction of the crystalline metal aluminosilicate zeolite of the molecular sieve type crystal whereby sodium vapors are adsorbed by said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type; and cooling in an inert atmosphere said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type containing said adsorbed sodium vapor whereby elemental sodium is retained in the inner adsorption region of said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type.

6. A process for preparing an elemental lithium-containing rigid, three-dimensional crystalline metal aluminosilicate zeolite of the molecular sieve type which comprises dehydrating a rigid, three-dimensional, crystalline metal aluminosilicate zeolite of the molecular sieve type capable of adsorbing dehydrating oxygen internally at the normal boiling point of oxygen whereby substantially all of the water of hydration of said crystalline metal aluminosilicate zeolite of the molecular sieve type is removed; intimately contacting in an inert atmosphere said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type with molten lithium metal at a temperature below the temperature of destruction of the crystalline metal aluminosilicate zeolite of the molecular sieve type crystal whereby lithium vapors are adsorbed by said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type; and cooling in an inert atmosphere said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type containing said 12 adsorbed lithium vapor whereby elemental lithium is re tained in the inner adsorption region of said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type.

7. As a new composition of matter dehydrated rigid three-dimensional crystalline metal aluminosilicate zeolite of the molecular sieve type chosen from the group consisting of zeolite A, zeolite D, zeolite L, zeolite R, zeolite S, zeolite T, zeolite X, zeolite Y, chabazite, faujasite, erionite, mordenite, gmelinite and the calcium form of analcite containing at least one elemental alkali metal in the inner adsorption region.

8. A composition of matter as described in claim 7 wherein the rigid three-dimensional crystalline metal aluminosilicate zeolite of the molecular sieve type is zeolite A.

9. A composition of matter as described in claim 7 wherein the rigid three-dimensional crystalline metal aluminosilicate zeolite of the molecular sieve type is zeolite X.

10. A process for preparing an elemental alkali-metalloaded rigid three-dimensional crystalline metal aluminosilicate zeolite of the molecular sieve type which comprises dehydrating a rigid three-dimensional crystalline metal aluminosilicate zeolite of the molecular sieve type chosen from the group consisting of zeolite A, zeolite D, zeolite L, zeolite R, zeolite S, zeolite T, zeolite X, zeolite Y, chabazite, faujasite, erionite, mordenite, gmelinite and the calcium form of analcite whereby substantially all of the water of hydration of said crystalline'metal aluminosilicate zeolite of the molecular sieve type is re moved; intimately contacting in an inert atmosphere said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type with the vapor of at least one alkali metal, the temperature of said vapor being below the temperature of crystal destruction for said crystalline metal aluminosilicate zeolite of the molecular sieve type, whereby said metal vapor is adsorbed by said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type; and cooling said dehydrated crystalline metal aluminosilicate zeolite of the molecular sieve type containing said adsorbed metal vapor in an inert atmosphere whereby said adsorbed elemental alkali metal is retained in the inner adsorption region of said crystalline metal aluminosilicate zeolite of the molecular sieve type.

11. A process as described in claim 10 wherein the rigid three dimensional crystalline metal aluminosilicate is zeolite A.

12. A process as described in claim 10 wherein the rigid three dimensional crystalline metal aluminosilicate is zeolite X.

References Cited in the file of this patent UNITED STATES PATENTS 1,840,450 Jaeger et al. Jan. 12, 1932 2,306,610 Barrer Dec. 29, 1942 2,413,134 Barrer Dec. 24, 1946 2,617,712 Bond Nov. 11, 1952 2,859,257 Hess Nov. 4, 1958 2,882,243 Milton Apr. 14, 1959 2,882,244 Milton Apr. 14, 1959 

1. AS A NEW COMPOSITION OF MATTER A DEHYDRATED RIGID, THREE-DIMENSIONAL, CRYSTALLINE METAL ALUMINOSILICATE ZEOLITE OF THE MOLECULAR SIEVE TYPE CAPABLE OF ADSORBING OXYGEN INTERNALLY AT THE NORMAL BOILING POINT OF OXYGEN CONTAINING AT LEAST ONE ELEMENTAL ALKALI METAL IN THE INNER ADSORPTION REGION. 